Based on the export data of HS-6 products from 222 countries from 2002 to 2019, this paper estimates the three margins of export of each country, and then uses the Heckman two-stage model to explore the impact of digital infrastructure on the three margins of export.It is found that digital infrastructure inhibits the growth of export extensive margin, but has a positive effect on price margin and quantity margin.Although the overall effect of the three coupling factors is negative, this phenomenon mainly occurs in developing countries, and the improvement of digital infrastructure plays a positive role in the export trade of developed countries, and this effect is also different due to the heterogeneity of products.Further discussion shows that total factor productivity, economic freedom and innovation ability can play a mediating role in the process of digital infrastructure influencing the triple margin of export, and the intensity margin is mainly reflected in the process.